For a battery pack including a plurality of cells, in order to prevent overdischarge and overcharge caused by fluctuations in state of charge (SOC) among the cells, a technology of performing capacity adjustment depending on the fluctuations among the cells to equalize the capacities is conventionally known (see, for example, Patent Literature 1).
In this technology, a discharge circuit is provided for each of a plurality of cells constituting a battery pack, and a cell having a higher state of charge (SOC) is discharged so that the state of charge (SOC) of the cell may be coincident with state of charge (SOC) of cells having lower state of charge (SOC), to thereby adjust the state of charge (SOC) to be equal to one another.